If you want the fastest 13.5T spec motor that's currently on the market, then get the Punisher, it's not ROAR approved, but just as fast (if not faster) than any $150 team motor on the market. The owner at our track is allowing the Punisher to help keep costs down and eliminate motor wars in the 13.5T class:
Trinity - Punisher 13.5t World's Fastest Spec Class Sensored Brushless - PUN1001 - Active Powersports

These motors have tons of torque so you can gear them up higher than traditional spec motors. They like to have the timing set around 47° too.